Optical waveguides, such as fibers and planar waveguides, which take advantage of total internal reflection have been used in a wide range of sensing, communication, and illumination applications. Light can be delivered through optical fibers with great efficiency over long distances because of the perfect mirroring that is provided by the core/cladding dielectric index step interface. Typically, the optical field in an optical fiber element is entirely confined because of this core/cladding interface.